Diagnostic Challenges in Pediatric Hemophagocytic Lymphohistiocytosis.

2021

2021 Mar 24

1573-2592

<p>Hemophagocytic lymphohistiocytosis (HLH) is a syndrome of severe immune dysregulation that encompasses a broad range of underlying genetic diseases and infectious triggers. Monogenic conditions, autoimmune diseases, and infections can all drive the phenotype of HLH and associated immune hyperactivation with hypercytokinemia. A diagnosis of HLH usually requires a combination of clinical and laboratory findings; there is no single sensitive and specific diagnostic test, which often leads to "diagnostic dilemmas" and delays in treatment initiation. Ferritin levels, one of the most commonly used screening tests, were collected across a large tertiary care pediatric hospital to identify the positive predictive value for HLH. Herein, we present several cases that illustrate the clinical challenges of confirming an HLH diagnosis. Additionally, we report on the utility of establishing a formal multi-disciplinary group to aid the prompt diagnosis and treatment of patients presenting with HLH-like pathophysiologies.</p>

10.1007/s10875-021-01025-3

J Clin Immunol

33761058

Human Adenovirus 7-Associated Hemophagocytic Lymphohistiocytosis-Like Illness: Clinical and Virological Characteristics in a Cluster of Five Pediatric Cases.

2020

2020 Aug 31

1537-6591

<p><strong>BACKGROUND: </strong>Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening condition of immune dysregulation. Children often suffer from primary genetic forms of HLH, which can be triggered by infection. Others suffer from secondary HLH as a complication of infection, malignancy, or rheumatologic disease. Identifying the exact cause of HLH is crucial, as definitive treatment for primary disease is hematopoietic stem cell transplant. Adenoviruses have been associated with HLH but molecular epidemiology data are lacking.</p>

<p><strong>METHODS: </strong>We describe the clinical and virologic characteristics of 5 children admitted with adenovirus infection during 2018-2019 who developed HLH or HLH-like illness. Detailed virologic studies, including virus isolation and comprehensive molecular typing were performed.</p>

<p><strong>RESULTS: </strong>All patients recovered; clinical management varied but included immunomodulating and antiviral therapies. A genetic predisposition for HLH was not identified in any patient. Adenovirus isolates were recovered from 4/5 cases; all were identified as genomic variant 7d. Adenovirus type 7 DNA was detected in the fifth case. Phylogenetic analysis of genome sequences identified two clusters - one related to strains implicated in 2016-2017 outbreaks in Pennsylvania and New Jersey, the other related to a 2009 Chinese strain.</p>

<p><strong>CONCLUSIONS: </strong>It can be challenging to determine whether HLH is the result of an infectious pathogen alone or genetic predisposition triggered by an infection. We describe 5 children from the same center presenting with an HLH-like illness after onset of adenovirus type 7 infection. None of the patients were found to have a genetic predisposition to HLH. These findings suggest that adenovirus 7 infection alone can result in HLH.</p>

10.1093/cid/ciaa1277

Clin. Infect. Dis.

32866230

Multisystem inflammatory syndrome in children and COVID-19 are distinct presentations of SARS-CoV-2.

2020

2020 Jul 30

1558-8238

<p><strong>BACKGROUND: </strong>Initial reports from the Severe Acute Respiratory Coronavirus 2 (SARS-CoV-2) pandemic described children as being less susceptible to Coronavirus Disease 2019 (COVID-19) than adults. Subsequently, a severe and novel pediatric disorder termed Multisystem Inflammatory Syndrome in Children (MIS-C) emerged. We report on unique hematologic and immunologic parameters that distinguish between COVID-19 and MIS-C and provide insight into pathophysiology.</p>

<p><strong>METHODS: </strong>We prospectively enrolled hospitalized patients with evidence of SARS-CoV-2 infection and classified them as having MIS-C or COVID-19. Patients with COVID-19 were classified as having either minimal or severe disease. Cytokine profiles, viral cycle thresholds (Cts), blood smears, and soluble C5b-9 values were analyzed with clinical data. Twenty patients were enrolled (9 severe COVID-19, 5 minimal COVID-19, and 6 MIS-C). Five cytokines (IFN-γ, IL-10, IL-6, IL-8 and TNF-α) contributed to the analysis. TNF-α and IL-10 discriminated between patients with MIS-C and severe COVID-19. Cts and burr cells on blood smears also differentiated between patients with severe COVID-19 and those with MIS-C.</p>

<p><strong>CONCLUSION: </strong>Pediatric patients with SARS-CoV-2 are at risk for critical illness with severe COVID-19 and MIS-C. Cytokine profiling and examination of peripheral blood smears may distinguish between patients with MIS-C and severe COVID-19.</p>

10.1172/JCI140970

J. Clin. Invest.

32730233